The present invention relates to a motor-vehicle headlamp.
The present invention relates more particularly to a motor-vehicle headlamp which is intended to produce at least one regulatory light beam, especially of the main-beam or of the dipped-beam type, of the type including a main optical system which comprises, arranged from rear to front overall along a main optical axis, a main light source, a main reflector of the elliptical type a first focus of which is situated in the vicinity of the source, and a converging main lens a focal plane of which passes close to a second focus of the main reflector.
In the motor-vehicle headlamps which include at least one main light source arranged within a reflector of generally parabolic shape or a reflector of the complex-surface type, it is known to arrange a secondary light source in a region of the reflecting wall of the reflector which is not essential to the forming of the regulatory light beam associated with the headlamp. This secondary source makes it possible to form a regulatory indicator beam of the position-light type.
According to the regulations in force, the position-light regulatory indicator beam, also called sidelight or sidelamp, has to shed light overall in all directions situated to the front of the headlamp with a relatively low luminous intensity compared to a main lighting beam such as a dipped beam or a main beam.
However, the arranging of a secondary light source in a reflecting wall of a main reflector cannot be envisaged for a headlamp equipped with a reflector of the elliptical type and with a lens.
This is because, since the main light source is arranged at the focus of the ellipse formed by the reflector, then the secondary light source absolutely must be arranged in a region which is very xe2x80x9cdefocusedxe2x80x9d and very much offset radially with respect to the main optical axis.
Consequently, the light beam produced by the secondary source at the exit from the lens is oriented mainly in a single direction very much inclined with respect to the optical axis. The luminous intensity is therefore not sufficient in the other directions, especially in the axial direction, to fulfil the regulatory requirements associated with a position-light beam.
Moreover, the headlamps with an elliptical reflector generally include a partial-shading device or mask, which is interposed axially between the reflector and the lens, with a view to shading some of the light rays emitted by the main light source so as to produce the corresponding regulatory light beam.
In the case of a headlamp forming a dipped beam, the mask is intended to shade mainly the light rays which would be directed upwards at the exit from the optical system. The mask is therefore arranged in front of the lower half of the outlet aperture of the elliptical reflector.
In this case, only the region of the reflecting wall of the elliptical reflector which is situated at the bottom, behind the mask, is not essential to implementing the main function and can therefore accommodate a secondary light source.
The light rays emitted by the secondary source then undergo the same shading effect as the main source. The light beam at the lens exit is therefore not correctly distributed in all directions, which does not allow it to satisfy the regulatory requirements.
Generally, when the main headlamps are of the elliptical-reflector type, it is then necessary to arrange the secondary light source outside the main headlamps, which is penalising especially in terms of costs and of bulk.
Moreover, the regulations of certain countries makes provision to oblige motor manufacturers to equip their vehicles with headlamps which produce a specific indicator beam, called xe2x80x9cDay Running Lightxe2x80x9d or xe2x80x9cdaytime lightxe2x80x9d, and which are intended to be lit permanently when driving by day.
Currently, this new indicating function requires a specific headlamp to be produced, dedicated to producing this regulatory daytime light beam.
There therefore exists a requirement for the design of a headlamp making it possible, in addition to at least one main function such as a dipped-beam function or main-beam function, to perform a secondary indicating function such as a position-light or daytime light function.
The invention aims to remedy the above-mentioned drawbacks, by proposing a headlamp of the elliptical type which is simple and economical, and which makes it possible to produce an indicator beam, in addition to at least one main lighting function such as a dipped beam or a main beam.
To that end, the invention proposes a motor-vehicle headlamp which is intended to produce at least one regulatory light beam, especially of the main-beam or dipped-beam type, of the type including a main optical system which comprises, arranged from back to front overall along a main optical axis, a main light source, a main reflector of the elliptical type a first focus of which is situated in the vicinity of the source, and a converging main lens a focal plane of which passes close to a second focus of the main reflector, characterised in that it includes a secondary optical system comprising:
a secondary light source which is arranged behind the main lens and off the path of the light rays emitted by the main light source;
and an optical distribution element which is interposed between the secondary light source and the exit surface of the main lens, which receives the light rays emitted by the secondary source on its entry surface and which distributes them over its exit surface, in such a way as to form, at the exit from the main lens, a secondary regulatory beam for indicating, especially of the position-light type or of the daytime-light type.
According to other characteristics of the invention:
the exit surface of the optical distribution element is adjacent to a portion of the entry surface of the main lens;
the optical distribution element is formed in a peripheral portion of the main lens;
the optical distribution element is a secondary lens;
the secondary light source and the optical distribution element are aligned generally along a secondary optical axis which is substantially parallel to the main optical axis;
the secondary optical system includes means designed to concentrate the light rays emitted by the secondary source onto the entry surface of the optical distribution element;
the secondary light source is arranged within a secondary reflector of generally parabolic or elliptical shape;
the structure of the secondary reflector is formed by moulding in a single piece with the structure of the main reflector.